Is it better to recognize one's own insignificance in order to arrive at an understanding of the greatness of God? Or is it better to focus on the greatness of God in order to arrive at a true level of humility?This is the question they posed to their Rebbe, the Maggid of Mezritch.
This Hanukkah it occurs to me that this question mirrors the two methods of lighting the hannukiah put forward by Beit Hillel and Beit Shammai. Beit Hillel says you start with a single light, with the humility of your own insignificance and then you build to many lights recognizing the greatness of HaShem's presence in the world. Beit Shammai says you start with all the beautiful greatness of HaShem's many lights and then work your way down to the smallness of your one little light.
The Maggid's answer to the original question is in line with the Halakha as well: they are both the words of the living Torah. But it is more correct (safer) to start from one's own smallness in serving HaShem.
And so that's another reason we start with just the one little light on the first night of Hannukah.